.. _Compression:

Compression
=========================

Essential Materials
-------------------

Download this: `7-zip Portable <http://portableapps.com/apps/utilities/7-zip_portable>`_

Essential Skill
---------------
Working with compression is essential for remote sensing.  Remote sensing data
is often very large and is typically delivered in a compressed format.  Students
will need to be able to install and use compression software to complete lab
assignments.

Objective
*********
Students will understand how to compress and uncompress files using `7-zip Portable <http://portableapps.com/apps/utilities/7-zip_portable>`_

Procedure
*********
Review the following demonstration video and practice compressing and uncompressing
files on your own.

.. raw:: html

  <center><iframe width="853" height="480" src="//www.youtube.com/embed/BnozYJmEAhg" frameborder="0" allowfullscreen></iframe></center>


Python
******

You can also extract tar.gz files using Python code and the tarfile module in
the standard library::

    import tarfile

    tar = tarfile.open('C:/path/to/tarfile/tfile.tar.gz', 'r:gz')
    tar.extractall('C:/output/path/')